1. Field of the Invention
The present invention pertains to a downhole gas-liquid separator device insertable in a wellbore and characterized by centrifugal separation inducing spiral baffles and a cross-over duct for directing the flow of gas up the wellbore annulus.
2. Background
In certain wells which produce hydrocarbon liquids, for example, the amount of gas entering the well and entrained in the liquid entering the well may be significant. Subterranean reservoirs which are subjected to pressurized gas injection to stimulate oil flow may produce gas commingled with the oil or gas may migrate to the production wells and flow into the wells at perforations spaced from the perforations which are producing primarily liquids. If the gas and liquid are required to be produced to the surface through the same conduit, elaborate separation and treatment facilities usually must be provided, which may require substantial reduction of the gas pressure during treatment thereof and thereby requiring costly recompression of the gas for transport or reinjection processes.
U.S. patent application Ser. No. 08/020,524, filed Feb. 19, 1993 to Jean S. Weingarten, et al, and assigned to the assignee of the present invention, now U.S. Pat. No. 5,343,945 describes certain systems for separating gas and oil in a wellbore and for transporting the separated gas and oil to the surface through the wellbore annulus and through a production tubing string, respectively. However, many wells which initially produce largely gas or liquid without much production of the other phase are structurally configured for production of the dominant phase and the original completion structure for the well is not easily adapted for downhole gas-liquid separation. Later in the life of the well, the increased production of mixed phase flow presents the aforementioned treatment problems. Of course, it is highly desirable to effect downhole separation of gas and oil without major refitting of the wellbore structural components. However, with the present invention, anticipation of expected conversion or installation of a separator device can be carried out with minimal cost and a separator device installed later in the production life of the well. It is with a view to solving this type of problem in downhole gas-liquid separator systems that the present invention has been developed which provides a unique solution to downhole gas and liquid separation in fluid production wells.